Ukraine accused Russia on Saturday of invading a region bordering Crimea and vowed to use “all necessary measures” to ward off an attack that came on the eve of the peninsula’s breakaway vote.

The dramatic escalation of the most serious East-West crisis since the Cold War set a tense stage for the referendum on Crimea’s secession from Ukraine in favour of Kremlin rule — a vote denounced by both the international community and Kiev.

The predominantly Russian-speaking Black Sea region of two million people was overrun by Kremlin-backed troops days after the February 22 fall in Kiev of a Moscow-backed regime and the rise of nationalist leaders who favour closer ties with the West.

President Vladimir Putin defended Moscow’s decision to flex its military muscle by arguing that ethnic Russians in Ukraine needed “protection” from violent ultranationalists who had been given free reign by the new Kiev administration.

According to the Ukrainian military website the army stopped Russian troops in Crimea from advancing inland.
The Ukrainian Military website reported:

Today, 15 March 2014, forces of the Armed Forces of Ukraine was halted by the penetration of the Armed Forces of the Russian Federation on the territory of Kherson Oblast from the “Arabatka.” Response was made ​​immediately.

Russian troops returned to their previous location.

In order immediate response to provocation from the Ukrainian side were raised forces Army Aviation Armed Forces of Ukraine and airmobile battalion strength.

The Ukrainian military added this on the Russian assault in the Kherson region.

Ministry of Foreign Affairs of Ukraine expresses its strong and categorical protest against the landing on March 15, 2014 near the village Strilkove, Kherson region of troops of the Russian Federation Armed Forces in a number of 80 military personnel, and seizure of the village Strilkove with the support of 4 helicopter gunships and 3 armored combat machines.

Ukraine Foreign Ministry declares the military invasion by Russia and demands the Russian side to immediately withdraw its military forces from the territory of Ukraine.

Ukraine reserves the right to use all necessary measures to stop the military invasion by Russia.